chemical changes and electrolysis Flashcards
Gain of oxygen is (a) and the loss of oxygen is (b)
(a) oxidation
(b) reduction
Is the more reactive a metal is, the more easily it loses electrons?
Yes
What do metals that react with water give?
Metal hydroxide and hydrogen gas.
What do metals that react with a dilute acid give?
Metal salts and hydrogen gas.
More reactive metals will displace (a) reactive metals from solutions of metal (b)
(a) less
(b) salts
What is the phonetic method of remembering the reactive series?
PoSLiCaMZIC.
Where are metals from the Earth’s crust found?
In rocks called ores, they contain enough metal to make it worthwhile to use them.
These metals can be extracted using electrolysis because they are more reactive than carbon and their oxides are not reduced by heating with carbon.
Potassium, sodium, lithium, calcium, magnesium, aluminium.
These 3 metals are less reactive than carbon and therefore their oxides can be reduced to the metal by heating with carbon.
Zinc, iron, copper.
These metals are found uncombined and do not have to be extracted.
Gold and silver.
What is the reason acids have similar properties?
They all contain hydrogen and when in aqueous solution they all give hydrogen ions.
What acids react with metals to form salts and hydrogen?
Hydrochloric and sulfuric.
(a) are soluble metal hydroxides; bases are (b) metal oxides and hydroxides.
(a) Alkalis
_(b)_insoluble
acid + carbonate -> (a) + (b) + (c)
(a) salt
(b) water
(c) carbon dioxide
When is an aqueous solution formed?
When a substance dissolves in water.
In neutralisation, H+ and OH- react to give what?
Water.
A concentrated solution of an acid has a
(a) amount (in moles) of the acid dissolved in the same (b) of water than a (c) solution.
(a) greater
(b) volume
(c) dilute
A strong acid like hydrochloric acid is completely/partially ionised in aqueous solution. A weak acid like ethanoic acid is completely/partially ionised in aqueous solution.
completely
partially
True or false: Strong is the same as concentrated and weak is the same as dilute.
False.
What happens to the H+ ions if the pH value of a solution decreases by 1 unit.
They increase by 10 times or 1 order of magnitude.